This invention deals generally with crop harvesting machines, such as mowers, mower-conditioners, and windrowers, and more specifically with a rear discharge header with an auger conveyor that transports the crop to one side of the header where it is discharged toward the rear of the machine.
It is well established that one way to reduce the subsequent work on a harvested field is to pass the crop mower or mower-conditioner in opposite directions for successive cuts, but to always discharge the crop from one side of the mower. This pattern of cutting produces what is known as double windrows, that is, two side by side windrows.
There are several patents which disclose such machines. U.S. Pat. No. 4,022,005 by Case describes a double windrowing machine that uses multiple parallel belts to move the crop to one side of the machine where it is discharged. The belts have lugs to engage the crop and finger-like strippers are mounted at the discharge end of the belts to assure that the crop is removed from the lugs. However, conveyor belts have problems associated with their structure. It is well known that conveyor belts require frequent maintenance. They have problems in tracking on their drive systems, and for crop mowers, they do not function well under widely different crop conditions.
U.S. Pat. No. 4,392,339 to Berlivet et al uses a more reliable auger conveyor to move crop from its usual center discharge location to a location on one side of the machine, and takes the auger conveyor out of service on alternate passes through the crop by raising it into a vertical position. Berlivet""s side discharge auger conveyor shoots the crop straight out the side of the machine, and the location and width of the resulting windrow is highly dependent upon the crop characteristics.
It would be very beneficial to have a reliable side discharge system for a crop mower that would lay down a windrow of predictable width and in a predictable location regardless of the condition of the crop itself.
The present invention uses an auger conveyor to accept cut crop material from all along the cutting unit, move it to one side of the header, and discharge it rearward in a well defined windrow outside the track of the wheels of the propelling vehicle. This action is accomplished by the use of an auger conveyor with unidirectional flow across the width of the header, with paddles mounted on the auger conveyor center tube at the discharge end of the auger conveyor and with the paddles and a rear discharge opening located beyond the track of the vehicle wheel. The rotating paddles then discharges the crop beside the vehicle wheel, but actually discharges the crop rearward, and the width of the discharge opening for the paddle determines the width of the resulting windrow regardless of the crop condition.
The invention also includes other features that improve the performance of the rear discharge conveyor. One feature is that rather than using the conventional auger pitch of 1.0; which is used in most crop auger conveyors, the present invention is designed with a pitch of 1.5. Thus, instead of moving the crop material the distance of one auger diameter for each revolution of the auger conveyor, the invention moves the material 1xc2xd times the diameter of the auger conveyor for every revolution. The faster displacement of the crop material prevents clogging of the auger conveyor with heavier crop material. The auger flighting can also be single or double, and, in fact, two flighting sets are desirable.
The another feature of the invention that improves performance is the use of a smaller center tube diameter for the paddle section of the rear discharge apparatus than for the auger conveyor section. For the rotating paddles to change the direction of and discharge crop material as fast as the auger conveyor feeds it into the paddle section, particularly with heavier crop material, it is beneficial for the center tube at the discharge to be smaller than the size of the auger conveyor center tube in order to accommodate the volume of crop of the full width of the cut. Therefore, for rear discharge units that are used with adverse crop conditions, as opposed to enlarging the auger conveyor trough to accommodate larger crop volume, the paddle section of the rear discharge apparatus is constructed with a smaller diameter center tube than the auger conveyor section. For the preferred embodiment, the auger conveyor section has a center tube diameter of 10 inches and the flights have outside diameters of 20 inches, while the paddles are mounted on a 5 inch diameter center tube and extend to the same 20 inch diameter as the flights. This configuration permits the trough for the auger conveyor section to extend over the paddle section with no discontinuity.
There are also two features of the present invention that permit adjustment of the width of the windrow produced. It is very desirable to maintain the outer edge of the windrow at a reasonable distance from the edge of the cut crop, and more importantly, from the boundary of the crop that will be cut later. If the windrow were located at the very edge of the uncut crop, the machine operator would have a difficult time preventing pickup of some of the windrow, and this can cause fouling of the crop cutting mechanism. The best arrangement is to have the windrow deposited somewhat inboard from the edge of the area of the cut. Such a location provides leeway for the machine operator to cut the standing crop but avoid the windrow. However, as with so many aspects of mowers, the motion imparted to the cut crop varies with the type of crop and with its moisture content, thus making it difficult to use permanently fixed structures to control the placement of the windrow.
The present invention includes an angularly adjustable swathboard protruding rearward and pivoting at the outboard sideshield of the header. This angled swathboard can narrow the crop flow path as the crop is discharged out the rear discharge opening by the paddle. The adjustable angle permits the swathboard to be oriented in a range from almost straight back to a significant angle, and thereby the windrow can be deposited at any desirable spacing from the uncut crop.
There is another very simple adjustment available at the inboard side of the rear discharge window that is used to reduce the width of the deposited windrow when crop conditions require it. To accomplish the reduction of windrow width there is added to the auger conveyor trough an additional section of sheet metal to close off part of the rear discharge opening. This additional section is shaped with the same curve as the auger trough to which it is bolted and is easily added or removed as needed.
The present invention thereby provides a reliable rear discharge crop header, that not only discharges varying condition crop material at the edge of the cut crop area, but also produces a neatly shaped windrow, with no scattering regardless of crop condition, to facilitate complete pickup of the side by side double windrow.